+ *
+ * @param fd File descriptor of stdin (normally 0)
+ * @param allow_sigs Allow Ctrl-C, Ctrl-Z to generate signals rather than
+ * be handled by U-Boot
+ */
+void os_tty_raw(int fd, bool allow_sigs);
+
+/**
+ * Restore the tty to its original mode
+ *
+ * Call this to restore the original terminal mode, after it has been changed
+ * by os_tty_raw(). This is an internal function.
+ */
+void os_fd_restore(void);
+
+/**
+ * Acquires some memory from the underlying os.
+ *
+ * \param length Number of bytes to be allocated
+ * \return Pointer to length bytes or NULL on error
+ */
+void *os_malloc(size_t length);
+
+/**
+ * Free memory previous allocated with os_malloc()/os_realloc()
+ *
+ * This returns the memory to the OS.
+ *
+ * \param ptr Pointer to memory block to free
+ */
+void os_free(void *ptr);
+
+/**
+ * Reallocate previously-allocated memory to increase/decrease space
+ *
+ * This works in a similar way to the C library realloc() function. If
+ * length is 0, then ptr is freed. Otherwise the space used by ptr is
+ * expanded or reduced depending on whether length is larger or smaller
+ * than before.
+ *
+ * If ptr is NULL, then this is similar to calling os_malloc().
+ *
+ * This function may need to move the memory block to make room for any
+ * extra space, in which case the new pointer is returned.
+ *
+ * \param ptr Pointer to memory block to reallocate
+ * \param length New length for memory block
+ * \return pointer to new memory block, or NULL on failure or if length
+ * is 0.
+ */
+void *os_realloc(void *ptr, size_t length);
+
+/**
+ * Access to the usleep function of the os
+ *
+ * \param usec Time to sleep in micro seconds
+ */
+void os_usleep(unsigned long usec);
+
+/**
+ * Gets a monotonic increasing number of nano seconds from the OS
+ *
+ * \return A monotonic increasing time scaled in nano seconds
+ */
+uint64_t os_get_nsec(void);
+
+/**
+ * Parse arguments and update sandbox state.
+ *
+ * @param state Sandbox state to update
+ * @param argc Argument count
+ * @param argv Argument vector
+ * @return 0 if ok, and program should continue;
+ * 1 if ok, but program should stop;
+ * -1 on error: program should terminate.
+ */
+int os_parse_args(struct sandbox_state *state, int argc, char *argv[]);
+
+/*
+ * Types of directory entry that we support. See also os_dirent_typename in
+ * the C file.
+ */
+enum os_dirent_t {
+ OS_FILET_REG, /* Regular file */
+ OS_FILET_LNK, /* Symbolic link */
+ OS_FILET_DIR, /* Directory */
+ OS_FILET_UNKNOWN, /* Something else */
+
+ OS_FILET_COUNT,
+};
+
+/** A directory entry node, containing information about a single dirent */
+struct os_dirent_node {
+ struct os_dirent_node *next; /* Pointer to next node, or NULL */
+ ulong size; /* Size of file in bytes */
+ enum os_dirent_t type; /* Type of entry */
+ char name[0]; /* Name of entry */
+};
+
+/**
+ * Get a directionry listing
+ *
+ * This allocates and returns a linked list containing the directory listing.
+ *
+ * @param dirname Directory to examine
+ * @param headp Returns pointer to head of linked list, or NULL if none
+ * @return 0 if ok, -ve on error
+ */
+int os_dirent_ls(const char *dirname, struct os_dirent_node **headp);
+
+/**
+ * Get the name of a directory entry type
+ *
+ * @param type Type to cehck
+ * @return string containing the name of that type, or "???" if none/invalid